This invention relates generally to an axially oriented optical system and more particularly to a system using a radial rotating light beam for scanning a medium mounted on a fixed cylindrical member.
Previously, scanners of X-ray exposed phosphor plates performed their function on a flat-bed or the external surface of a rotating drum. These systems have problems that increase the cost and reduce the quality of the X-ray image. The undesirable results obtained with a flat-bed or rotating drum system are caused by the continuous changing of the angles and distances of the light beam paths used for stimulating the phosphor of the X-ray exposed phosphor plates. Also, the collection of the stimulated light is performed with a different path and angle for each position on the phosphor plate, thereby requiring complicated, expensive compensation with a resultant reduction in quality. Additionally, the complications with attendant increases in cost are exacerbated when existing systems for supporting the phosphor plates do not maintain a fixed positioning during the scanning procedure.
Apparatus for radiation image read-out are known and are described, for example, in U.S. Pat. Nos. 4,886,968 and 5,396,081.
An optical system for an internal drum readout apparatus using a radial rotating light beam, which provides for minimizing distortion together with a reduction of cost and complexity cannot be found in the art.
Neither the prior art devices nor contemplated solutions for their deficiencies are capable of resulting in a digitizer apparatus providing a combination of reduction in cost with an increase in accuracy and quality.
In view of the aforementioned drawbacks of the conventional scanner systems, this invention provides a scanning system with a novel on-axis optical system to minimize distortion and avoid complex compensation introduced by currently used arrangements, while at the same time achieving cost reduction.
In addition, a light beam scanning system for digitizing X-ray exposed phosphor plates for storage and/or image display is provided.
There is thus provided, in accordance with a preferred embodiment of the present invention, a scanning apparatus, which includes a medium attached to a surface of a fixed, hollow cylindrical segment, the fixed, hollow cylindrical segment having a first longitudinal axis, a rotational radial laser beam rotating around the first longitudinal axis and arranged to scan said medium, and a light sensitive detector having a light acceptance direction along a second axis coinciding with the first longitudinal axis of the cylindrical segment.
Further, in accordance with a preferred embodiment of the present invention, the apparatus further includes at least one reflector for directing the beam towards the medium. The apparatus further includes transport apparatus for rotating and translating the laser beam.
Further, in accordance with a preferred embodiment of the present invention, the medium is a phosphor plate.
Further, in accordance with a preferred embodiment of the present invention, the reflecting unit may be a slanted mirror fixedly mounted for movement with the transport apparatus. A hole may be formed in the center of the slanted mirror for directing the laser beam therethrough. Furthermore, in accordance with a preferred embodiment of the present invention, the slanted mirror forms an angle in the range of 30-60 degrees relative to the longitudinal axis. The slanted mirror may be concave.
Further, in accordance with a preferred embodiment of the present invention, the apparatus further includes a rotating shaft, the laser beam being attached to the rotating shaft, wherein power is directed via slip rings attached to the rotating shaft.
Further, in accordance with a preferred embodiment of the present invention, the apparatus further includes a hollow shaft providing a beam path from the light source to the hole, and a mirror fixedly mounted in the hole for movement with the transport and rotated with the shaft for presentation of the beam along a radial from the axis to the medium.
Also, in accordance with a preferred embodiment of the present invention, the apparatus further includes a Fresnel lens mounted within the hollow cylindrical segment and proximate to the concave interior of the hollow cylindrical segment. The Fresnel lens has a longitudinal axis perpendicular to the longitudinal axis of the hollow cylindrical segment and the Fresnel lens has a hole formed in the center thereof to allow the beam and the receiving light emanating from the medium to pass through undisturbed.
Further, in accordance with a preferred embodiment of the present invention, the light emanating from the medium is refracted by the Fresnel lens the refracted light being reflected by the slanted mirror through the detector.
In addition, in accordance with a preferred embodiment of the present invention, there is also provided a scanning method. The method includes:
attaching a medium to a surface of a fixed, hollow cylindrical segment, having a first longitudinal axis;
arranging a rotational radial laser to rotate around the first longitudinal axis beam to scan the medium; and
detecting the rays reflected from the medium along a second axis, said second axis coinciding with the first longitudinal axis.
These and other advantages, features and objects will become more apparent from the following description taken in connection with the illustrative embodiments in the accompanying drawings.